1. Field of the Invention
This invention relates to a method of preparing a thickener-free consumption ice or frozen dairy dessert from a mixture of fermented milk constituents, including whey protein-rich products, and sugars, and optionally emulsifying agents, flavouring material and other conventional components by mixing those ingredients and freezing the mixture under aeration.
The term "consumption ice" as used herein refers to frozen dairy dessert produced from non-butter fat, sometimes referred to as `mellorine`.
2. The Prior Art
Such a method is known from U.S. Pat. No. 4,110,476, except that in that method always microcrystalline cellulose is utilized in the mix as a stabilizer and thickener. A yogurt based frozen dairy dessert without thickener is mentioned in a publication in Nordeuropaeisk Mejeri-tidsskrift 8 (1977) 257-259. The formulation comprises, in addition to saccharose, exclusively milk derived products, i.e. in addition to ordinary yogurt 5 different whey products, obtained by lactose hydrolysis, from whey and from purified lactose, by ion exchange extraction, by ultrafiltration and still other techniques. This technique is rendered unattractive by the large number of ingredients, some of which are not available unless at high cost.
Accordingly, one can attempt to employ a slightly simplified formulation, using as an ingredient, in addition to ordinary yogurt, a whey protein preparation, which may or may not be combined with conventional thickeners, as in the U.S. specification referred to. But there are objections to such thickeners, which, in general, must be specified as such or by a code on the package, because the consumer tends to be suspicious regarding such ingredients that are not familiar to him.
From a whey protein-enriched yogurt of a normal type, fermented at elevated temperature with cultures containing Lactobacillus bulgaricus and Streptococcus thermophilus, a thickener-free yogurt based frozen diary dessert be prepared by freezing under aeration, which yields a palatable frozen dairy dessert of fairly good texture. But then the product exhibits the disadvantage of a relatively low "overrun" which in general is substantially less than 80%.
"Overrun" is the increase in volume of the frozen frozen dairy mass caused by the air incorporated as a result of the aeration of the mix during freezing, expressed as a percentage by volume of the volume without aeration. Such frozen dairy dessert with low overrun has a firm but at the same time actually too solid a texture, it has a not so desirable high calorie content and is relatively costly, all as compared with an equivalent volume of frozen dairy dessert with high overrun rates.